Treatment of cellulosic material to increase its reactivity



FIP8509 R'EiERENQE Search Room at? an. 14, 1944 TREATMENT OF CELLULO SIC; MATERIAL TO INGREASEITS REACTIVITY tlchardr R eves... Y rs, N-

. aw gner. to: The-Chemical F-oundationti Incorporated. a. cornot ti n l Delaware No- Drawings Application' May -29; 1939. Serial No. 276 141;

1 Clainn (c1. 2603: 212).

This invention relatesto thetreatment oi cellulosic material to increase-its reactivity.-

As those skilled inthe art know; fewnatural chemical products have had as many, speculatively-- assigned" formulae as cellulose. At the present time, it-is generally accepted, asaworkinghypothesis thatthe cellulose. moleculeis comprised in 1 part of anhydroglucoset residues, con,- taining three..alcoholic hydroxyl: groupsfor'every six carbon atoms,

It has been shown (J aclcson and Judson Am. Chem. Soc. 59, 2049 (11.9.37); 60. .1- 98911938); that both cotton .and. wood cel ulose may eras ically. oxidized-bymeans-rofzad p riodic aci to. form. a p du t contains:- a de y i groups and which'ptoducti so bl -in hotwater and cold dilute acidsi. ;Th..,..c to secure as COmDlQEEEHIIk-QX, by treating cotton, for example for a p amount of periodic. acid. consumed;- by the fibers was determinedat .di-fierentdntervals. to thus correlatethe deg-reeofroxidation of the fibers with the, ability to ,-form a idyerwith. the fuchsin-sulphurous acid solution.. Theresultsci treatment of. this,character.are-indicated in, the following 430.-hours with strong; solution or: the; acid. table:

' Table Mercerized cotton fiber treated with 10cc. of 0.125 molar periodic acid at 20124? 0..

0.125 M perio dic d s d by sample Timeoi reatment Coloration after -miniat 20 0. witl juchsinsulphurous acid Action of dyed productwith cold-N110 sodium-hydroxide Untreated control 0.128 g. cotton 0.1204 g. cotton Purple 0.122 g. cotton 4 days.-- 0.86 or Purple-black--. 0.128 g. cotton 9 days.-. 1.32 cc do The major purpose of these investigations evidently was to correlate the chemical structure of starch and cellulose.

It has now been discovered that the chemical reactivity of cellulose may markedly be modified by a controlled or selective oxidation. Such modification has profound technological significance the extent or scope of which is illustrated didactically herein in respect to dyeing or dye acceptance of cellulosic fabrics.

It has been found that if cellulosic material, for example mercerized cotton fibers, is treated with relatively dilute periodic acid at moderate temperature new properties are imparted to the material particularly in respect to its action toward dyes.

The type of treatment to be given the fibers under the invention is illustrated by the following example:

} EXAMPLE I 0.12 g. samples of mercerized cotton fibers were treated with 10 cc. portions of 0.12 molar periodic acid at 20-24 C. The acid was allowed to act Complete loss of color, fiber intact. Gradual loss of color, fiber apparently intact.

Extensive loss of color and fiber disintegration, partly dissolved. Dissglved completely with loss of color.

As will be observed from inspection of the table, treatment of the control (mercerized cotton) with the dye solution produced but a faint coloration. Treatment of the dyed control with N 10 sodium hydroxide completely destroyed the color. However, when a similar sample of mercerized cotton fiber was treated for 15 minutes with the indicated dilute solution of periodic acid the dyeing was considerably enhanced, the dyed fabric being of a deeper color. It is particularly to be observed that such dye is apparently much more stable than that combined with the untreated control, for an equivalent treatment with the caustic solution effected less loss in color with no apparent attack on the cellulose fibers themselves.

The degree of oxidation of the cellulosic material by the periodic acid must be maintained within close if not critical limits in order to secure the desired improvement in reactivity. As will be observed from the table, as the time of treatment with the periodic acid is increased the absorbability of the fiber for the dye measurably increases as is indicated by the marked increase in depth of the color. However, such prolonged treatments are too drastic, for the fibers so treated, when immersed in the cold caustic solution not only completely lost color but the fibers themselves were partly. or completely dissolved.

In orderto'determine the commercialfeasibility of the treatmerit,-' a numberI-of other ex:- periments were conducted. It was found that preliminary treatment of cellulosic material, particularly cotton fibers with, periodic acid of the acid. When salts are used in lieu of the acid the optimum pH may be attained by utilizing a suitable mineral acid.

It will be appreciated that this type of treatment is of marked utility and has many ramifications in the art. The particular examples described-herein serveefiectively to illustrate the modifi,ation bft'he chemical activity of cellulosic material as a result of the invention. The treatment obviously has direct and immediate utility forthe. purpose of enhancing the dye acceptance under conditions controlled short ofcomplete oxidation insured the production of a cellulosic material of new characteristics.

reactive, so to speak, as is clearly indicated by This treatment renders the cellulosic material potentially of cellulosic fabrics. However, the treatment maybe employed in any circumstance in which cellulose is involved, especially as a chemically its acceptance of typical dyes, It was obvious that the preliminary mild treatment with 0.15, M. periodic acid markedly improves the amenability of the fabric to dyeing. For example,

the preliminarily treated material dyed with fuchsin-sulphurous acid solution develops a deep purple, whereas an untreated sample of the same .Iabric develops but a faint pink. This same marked difierential in dye acceptance and resulting color gradation obtains similarly when other dyes are employedas for example, o-tolyl hydrazene and p-nitro. phenyl-hydrazine.

As will be appreciated, the mechanism "of this reaction is difficult precisely to explain. It is i possible that the marked increase in reactivity of the cellulose is due to a' s'elective oxidation of one or-more of the alcoholic hydroxyl groups, conceivably those at positions 2 and 3. Whatever may be the action taking place, it is a fact that it is highly specific'o'r critical, both as to degree or time of treatment and as to the reactant employed.- It has been found, for example, that treatment of cellulosic material with equivalent amounts of perchloric acid will not impart the same increased reactivity to cellulose which is effected by treatment with periodic acid.

While periodic acid has been described herein ;containing reacting component. For example, the invention may be utilized in the plastic industry to produce new and improved forms of cellulose synthetic resins. The cellulosic starting material, such as cotton and other cellulosic 'fibers, after any desired preliminary treatment may be treated according to the invention, that is to say, with periodic acid solutions of bontrolledstrength and for predetermined periods of time, so as to oxidize or otherwise-chemically modify the cellulose molecule.

Thereafter the modified cellulose containing aldehydic groupings may be reacted with phenol so as-to effect'a condensation reaction through -the aldehydic linkage; Thereafter the initial condensation product may be submitted to treatments known in the art to-produce the various modified forms of the resin.

;.It will :therefore be understood that while particular treatments are described herein by way of examples, these are given to illustrate 1 the broader concept of the invention, namely,

the modification. ofthe cellulosic material to increase its chemical reactivity.

I claim: A method of modifying the chemical characteristics of cellulose, which comprises, subjecting the cellulose to the action of a 0.12-0.15 M.

as the preferred treating agent, it is to be understood that this is also intended to include its equivalents, i. e. .its salts, such as the sodium salt Q V r periodic acid solution, at room temperature for a Qperiod of less than 24 hours, tosecure only parcellulose.

{tiai oxidation of the RICHARD REEVES. 

